This application is based on Japanese Patent Application No. 2001-139630 filed on May 10, 2001, the disclosure of which is incorporated herein by reference.
The present invention relates to a rotor for a vehicular alternating current generator mounted on passenger cars, trucks, and the like.
In a rotor for a vehicular alternating current generator disclosed in JP-A-2000-125528 (U.S. Pat. No. 6,114,786), a field coil is wound around an insulating bobbin. The insulating bobbin has a coil-winding body around which the field coil is wound and flanges extending from both ends of the coil-winding body in a radially outward direction. One of the flanges has a first hook portion and a second hook portion to fix a coil winding finishing end that is extended from the outer peripheral surface of the field coil. The finishing end is extended in a radial direction along an axial end surface of the flange through the first hook portion, and extended further in the axial direction through the second hook portion. The second hook portion is positioned radially inside of the outer periphery of the field coil. Since the finishing end is held at a position where centrifugal force is small, the finishing end is fixed to the flange with adequate strength against the centrifugal force.
In this rotor, the finishing end is bent to form an angle with itself of substantially 90 degrees at the first hook portion. Therefore, if the finishing end is moved during post-treatment such as connection of the terminal end of the finishing end, the movement is likely to be transmitted to the coil-winding part of the field coil. As a result, the field coil is likely to easily loosen.
The present invention is made in view of the above problems, and it is an object to provide a rotor for a vehicular alternating current generator, the rotor being capable of restricting loosening of a field coil.
It is another object to provide a rotor for a vehicular alternating current generator in which a coil end of a field coil is tightly fixed.
In a rotor for a vehicular alternating current generator, a field core is press-fitted around a rotary shaft, and an insulating bobbin is fitted around the field core. The insulating bobbin has a cylindrical coil-winding body and a flange extending in a radially outward direction from an axial end of the coil-winding body. The flange has a first surface and a second surface opposite to each other. The first surface is on a side of the coil-winding body and the second surface is on an axial end of the bobbin. A field coil is wound around the coil-winding body of the bobbin. The flange is formed with a first hook portion, a second hook portion and a third hook portion. The first hook portion is to direct a coil winding finishing end of the field coil opposite to a winding direction of the field coil. The second hook portion is to direct the finishing end further in a radially inward direction. The third hook portion is to direct the finishing end further in an axial direction.
The finishing end is wound around the first hook portion and is opposed to the winding direction of the field coil axially outside of the bobbin, and directed in the radially inward direction with the second hook portion. The finishing end is extended in the radially inward direction along the second surface of the flange. The finishing end is directed further in the axial direction with the third hook portion. Accordingly, even if the finishing end hooked with the second and the third hook portions is moved axially outside of the bobbin, the movement of the finishing end is restricted at the first hook portion and not transmitted to a coil-winding part of the field coil. Therefore, the field coil is prevented from loosening.